title: A novel method for the direct determination of heparin concentration during cardiopulmonary bypass surgery.
abstract: BACKGROUND
  Heparin is the standard drug for anticoagulation treatment and is used in many cardiac surgical interventions to prevent blood clotting. The anticoagulation status is controlled by various clotting tests. However, these tests depend on parameters like temperature, hemodilution etc. and are thus not applicable for a direct monitoring of the heparin concentration. The aim of this prospective study was to test a novel light scattering assay (LiSA) for the direct determination of heparin concentration during cardiopulmonary bypass (CPB) surgery and to compare the heparin concentrations with routinely determined activated clotting time (ACT).
  
  
  METHODS
  The patient group consisted of 50 patients undergoing coronary bypass surgery with CPB. The coagulation status was monitored by the measurement of ACT, which was performed approximately every 30 min during surgery. Parallel to each ACT measurement, the heparin concentration was measured by LiSA.
  
  
  RESULTS
  For 70% of the patients, ACT and heparin concentration measured by LiSA correlated reasonably over the entire time course of the intervention. For 30% of the patients, an insufficient correlation or even no correlation at all was observed.
  
  
  CONCLUSIONS
  This study showed that LiSA enables the determination of intra-operative heparin levels. The lack of correlation between ACT and heparin concentration in a substantial group of patients shows that monitoring of heparin concentration is important. A more precise blood coagulation management, in particular, a precise administration of heparin and protamine, should be based on a combination of the measurement of heparin concentration and of ACT, but not on ACT alone.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Haselbach
authors.forename: Jürgen
authors.initials: J
authors.lastname: Maurer
authors.forename: Vitali
authors.initials: V
authors.lastname: Vogel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Harder
authors.forename: Christian Friedrich
authors.initials: CF
authors.lastname: Weber
authors.forename: Doan
authors.initials: D
authors.lastname: Baykut
authors.forename: Dirk
authors.initials: D
authors.lastname: Meininger
authors.forename: Harald
authors.initials: H
authors.lastname: Keller
authors.forename: Anton
authors.initials: A
authors.lastname: Moritz
authors.forename: Werner
authors.initials: W
authors.lastname: Mäntele
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000097:blood*; D015982:Bias; D001681:Biological Assay; D002315:Cardiopulmonary Bypass; D016903:Drug Monitoring / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006493:Heparin / Q000097:blood*; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014914:Whole Blood Coagulation Time
chemical_list: D000925:Anticoagulants; D006493:Heparin